Page 10 - PC 101 practical notes 24-25..

MANSOURA NATIONAL UNIVERSIY
PHARM D- CLINICAL PHARMACY LEVEL I PHARM. ANAL. CHEM. I (PC 101)

Standard Solutions:

It is a solution of known concentration & composition.

Types of standard solutions:

1. Primary Standard Solution:

♦ It is a solution whose concentration remains constant for a long

period of time.

♦ It is prepared directly by dissolving known weight of the primary

standard substance in a certain volume of solvent.

♦ Example: Na 2CO 3.

2. Secondary Standard Solution:

♦ It is a solution whose concentration can be only be known

approximately.

♦ The exact concentration of it is determined by a process called

"Standardization or Standardisation".

♦ Standardization must be done after the preparation of secondary

standard solutions to determine their exact concentration and

correct any error if present. That is done by:- Titrating the

secondary standard solution against a primary standard solution OR

against a previously standardized secondary standard.

♦ Examples: NaOH and HCl.

Remember: Solute + Solvent = Solution
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